Use APT pinning to fix the Sensu version

This stops version bouncing (and possible related breakage) when the
node's specified Sensu version is lower than the latest version
available in the repository, and the node is upgraded via apt-get
(without pinning, Sensu will be upgraded by APT, then downgraded at
next Chef client run).
Merge pull request #172 from pdf/apt_pin_version

Use APT pinning to fix the Sensu version
Add support for setting the log_level (sensu/sensu#542: Make logging configurable)
Merge pull request #173 from tomdz/log_level

Add support for setting the log_level (sensu/sensu#542: Make logging configurable)
Update Gemfile with librarian-chef

As of version 0.1.0, the librarian gem has split librarian-chef off into
it's own gem.
Merge pull request #175 from skymob/update_gemfile_with_chef_librarian

Update Gemfile with librarian-chef
Install rabbitmq before using rabbitmq group
Might as well put rabbitmq::mgmt_console at the top also
Merge pull request #176 from anowell/rabbitmq-group

Install rabbitmq before using rabbitmq group
ubuntu 12.04 installs redis from source, added miah's redis cb note to readme
Merge pull request #179 from portertech/redis

ubuntu 12.04 installs redis from source, added miah's redis cb note to readme
minor version bump, rabbitmq and redis recipe fixes
Merge pull request #180 from portertech/version

minor version bump, rabbitmq and redis recipe fixes
fixed & updated vagrant sensu stack, corrected redis recipe include position
Merge pull request #181 from portertech/vagrant

fixed & updated vagrant sensu stack, corrected redis recipe include position
[redis] switch to redisio cookbook
Merge pull request #185 from portertech/redis

Switch to redisio cookbook
[timeout] bumped sensu default version, check/mutator/handler timeout
Merge pull request #186 from portertech/timeout

bumped sensu default version, check/mutator/handler timeout
version bump